Background. Decades of research indicates people with less education and lower income have worse health, receive fewer needed services, and often have poorer healthcare outcomes, even in populations with universal coverage. Despite VA's role as a safety-net provider and commitment to equity, the limited evidence available suggests that higher socioeconomic status (SES) is associated with better outcomes in VA, as elsewhere. Patient SES may also influence health system performance. But this is difficult to track because the VA, like other health systems, does not routinely collect information on income or other SES measures. Currently, research studies and VA analyses use indirect proxy measures based on VA priority group or census data that are only rough approximations of individual SES. There is a need for a better measure. Specific Aims. The objective of this pilot study application is to evaluate the potential value and limitations of a newly available data source as an individual-level proxy for measures of SES. The Armed Services Vocational Aptitude Battery (ASVAB) is a series of tests administered to military enlistees at recruitment. Given the close correlation between aptitude test scores, which reflect a person's cognitive ability, and later life educational attainment, income, and wealth, Veterans' ASVAB results may be useful in capturing elements of SES for research, performance measurement, and other uses. The aims of this pilot study are: (1) Examine the VA population coverage, representativeness, and quality of the ASVAB data; (2) Using two distinct analytic subsamples and two income data sources, a) examine relationships between Veterans' ASVAB scores measured at enlistment and their present-day income, and b) assess the representativeness of the subsamples in regard to ASVAB-income relationships; and (3) determine whether ASVAB scores have added value in explaining individual variation in selected measures of current health and health behaviors (functional limitations, comorbidity burden, hemoglobin A1c in those with diabetes, and smoking status). Significance. The proposed research is well-aligned with HSR&D and VHA priorities: developing new measurement approaches for becoming a high-performing, continuously learning healthcare system, healthcare equity & health disparities, and improving Veterans' access to care. A better individual-level SES measure would have multiple important uses in VA, including in improving performance measurement to take patient SES into account and the predictive ability of models determining resource allocation, productivity expectations, and future access and capacity. Innovation. This study is highly innovative because it creatively addresses a major barrier to research, quality and performance measurement, and assessment and monitoring of equity in healthcare access and outcomes: lack of information on patient SES. The study does so by taking advantage of a promising new data resource?ASVAB scores?that was not previously evaluated for use to support Veterans later in life. Methods. The population is Veterans using VA healthcare services in 2010-2017. This will be a retrospective study using existing VA, American Community Survey, and Department of Defense ASVAB data. Veteran income data will come from the Annual Survey of Veteran Enrollees' Health and Healthcare and the VA's Health Eligibility Center (HEC). Descriptive and multivariable regression analyses will be conducted. Expected Results. This project will provide an understanding of the strengths and limitations of the data and evidence to assess whether the ASVAB-income relationships measured in available samples will hold in the broader VA population and ASVAB data will provide value-added to current measurement approaches. Next Step(s). Based on the results of this work, we plan to submit an Investigator-Initiated Research proposal (IIR) to develop and evaluate an SES index based on ASVAB scores and assess its value for risk adjustment in performance measurement.